Front end loader



v Filed Maggi 1946 4D., 6, 1949 l L. D. PFM; mL 2,490,155

FRONT END LOADER 2 Sheets-Sheet l l Rber/. YZ/fford Dec. 6, 1949 L. D. PFAU Erm.. 2,490,155

FRONT END LOADER 2 Sheets-Sheet 2 Filed May 27, 1946 7 /7 Y wf/WM5 24 www 7am@ Patented Dec. 6, 1949 FRONT END LOADER Leo D. Pfau,

Mayer, Minneapol Robert D. Tuiford, and Joleph E. is, Minn., assignors to Super Six Manufacturing Inc., Minneapolis, Minn., a corporation of Minnesota Application May 27, 1946, Serial No. 672,417

8 Claims. (CL 214-140) Our invention relates to power actuated front end loading apparatus for self-propelled vehicles, such as tractors, trucks, patrol graders and other automotive vehicles and relates particularly to apparatus of this character which may conveniently be embodied in attachments for conventional types of self-propelled vehicles and which are adapted to gather or scoop up material by pushing action at the front end of the vehicle and to subsequently elevate the material gathered,

' transport the same and dump the same from an elevated position for loading or piling.

This invention embodies improvements on the structure disclosed in the pending application of Leo D. Pfau, one of the applicants herein, entitled Loading device, Serial Number 559,603, iiled October 20, 1944.

It is an object of our present invention to further improve upon the emcient and commercially successful structure disclosed in said Pfau application to the end that lifting force is applied by thrust from below to the outer portion of the boom more uniformly and with less variance in power required throughout the entire lifting operation and with less friction on working parts; while maintaining the general underslung and simplified construction of said Pfau device as well as distribution of the load during elevation.

A further object is the provision of a simplified and highly eiiicient front end loader wherein elevation of the boom and load supported from the outer end thereof is' obtained through cantilever thrust and toggle connection between the power source (preferably hydraulic) and the outer or front end of the boom and wherein the applica tion of power and its connection with the cantilever boom swinging mechanism are disposed at all times in very low relation to the main frame of the vehicle chassis, the mounting of all 'parts being mainly below the tractor height and preferably at the level or below the level of the main chassis frame of the traction vehicle. With such structure, distribution of the load stress incurred by the elevation thereof is efilciently obtained during loading or gathering and during transportation of the load to the point cf dumping.

Another important object is the provision in combination with the cantilever thrust mechanism for elevating the boom, of means actuated by the same cantilever structure for automatically leveling and maintaining the load holder or bucket a predetermined pitch throughout the elevation of the load.

A more specific object is the provision of a front end loader attachment for tractors and the like wherein a source of power. preferably hydraulic, is applied by thrust from beneath the load to a forwardly extending swingable boom through the medium preferably of a bell crank lever-toggle principle wherein the bell crank is pivoted at a low point on the vehicle chassis and wherein all parts of the device are mounted below the overall height of the tractor with distribution of stresses and strains eilciently upon the frame and support of the traction vehicle and with elimination of upstanding or overhanging mountings or other parts to obstruct the vision and manipulation of the operator.

Another object is the provision in a loader of the class described, of cantilever equalizing connections between the longer arm of the bell crank, boom elevating mechanism and the boom whereby required thrust elevating power throughout the entire arc of elevation is reasonably constant.

A still further object is the provision in structure of the class described of an improved latch construction for releasing the load carrier to effect instant dumping through gravity and eiective upon dumping of a load to again lock the load carrier in cooperative loading and elevating relation to the boom.

These and other objects and advantages of our invention will be more apparent from the following description made in connection with the accompanying drawings, wherein like reference characters refer to similar parts throughout the several views and in which:

Fig. l is a perspective view showing an embodiment of our invention applied to the tractor of conventional type with the boom structure and load carrier disposed in fully elevated position for dumping of the load.

Fig. 2 is a side elevation of the same with the boom disposed in lowermost position for applying thrust in gathering a load and with the boom and cooperating parts shown in dotted lines in partially elevated position.

Fig. 3 is a similar side elevation showing the boom, load carrier and associated parts in almost fully elevated relation while showing an intermediately elevated position of said parts in dotted lines.

Fig. 4 is a detail cross section showing the equalizing linkage between the outer end of the bell crank mechanism and the boom taken approximately on the line I-I of Fig. 3 with the latch mechanism for the load carrier removed.

Fig. 5 is a side elevation of the outer portion of the boom and the load carrier in lowered position and showing our improved latch mechanism for controlling the dumping of the load and with some parts broken away and others shown in section.

angular plates of rigid material and having rolled r tubular, longitudinal edges Ila at one side Fig. 6 is a detail view mostly in top plan, showl crank levers are defined by the short sides of the ing the said latch mechanism and its relation triangular plates and in the form shown extend with the load carrier and equalizing linkage; nearly at right angles (from 90 to 120 degrees in Fig. 7 is a detail cross section taken on the line angulation) from the line of the longer bell crank 1`1 o1' Fig. 5; and arms Ma The corners of the bell crank levers Fig, 8 is a fragmentary, side view of the load 10 Il are heavily reinforced and are pivotally concarrier detached. nected in a predetermined relationship to boom In the drawings, our improved apparatus is pivots I3 with the pivot yokes I0c furnished by attached to a self-propelled vehicle, as shown, the stress absorbing mounting frame. in the form of a conventional farm tractor having Fluid connections preferably of the flexible type the usual chassis and large rear traction wheels (not Shown), are made in conventional manner W provided with the usual small front wheels F between the hydraulic cylinders I 6 and a hywhich are spaced closely apart and converge drallllc pump equipped With conventional Valve towards their lower perlpherles and are of much means and circulating system and controlled from smaller diameter than the rear wheels, W The a suitable box or control panel C mounted for heavy, rear axle housing designated as A jour- Convenient access to the driver. nais the axles of the rear wheels in conventional Elevating thrust is imparted to the outer p0rmanner and is preferably utilized as the base or tiion of the boom structure through an equalizing rear attachment medium for our apparatus lnkage comprising a cantilever action frame 1n- H Our improved loabder appaitus, preferably utiz dlcted eis a? entirey by tlliiinumerai l'lf :nd of zes a stress absor er moun ng frame compris- 5 IeC ang al' Orm all 00ml) ng a Da l 0 ransing a pair of heavy mounting tubes |g disposed versely extending and parallel, tubular sides I'Ia longitudinally along the two sides of the chassis interconnected by heavy link plates I 'lb which of the vehicle and each having telescoped in the all lldedt Ornithelllzvtrigillilllemlg atetliegif rear end thereof an adjustable extender tube or en S ere 0 a W C W n0 al rod I 0a which is rigidly connected with one end 30 sed lspeegve logglltudhl 'ugnmlt gltih of the rear axle A b suitable means such as a e 0u 1' en s 0 e e Cra evers e heavy u boit Sutebie means suon as a set lower side of the equalizing linkage or cantilever screw or clamp gob is interposed between the frame is pivotally connected by horizontal stub mounting tube in and the telescopen extender shafts or the like, Ilc which telescope withm the Illa to adjustably and longitudinally secure said 3 lower tube "a 0f the frame and which extend parts together. The forward ends of longitudinal also through heavy pivot sleeves d Secured t0 mounting tubes io are provided with pivot iorm tlie ends of their longeii bell crank arms of levers ing yokes IIJc and are rigidly and detachably con- '1 Theh cant level; 1 Iflkage firane n ncluzifs nected with suitable heavy mounting brackets 4 alslfls s ovnia gear L rigid s de inkllla es d or stub shafts provided by the tractor chassis or u EL maly t en?, er; ri Iflrmed or twe dei Wtlh leidlytattached thereto in t; ugaberioof comen' slevenllll; a son@ onsaldgsldr figxllrnglcagsvlll nag ional ractors. The mount ng rs are thus very rigidly afflled to the ltwr;l siriles :if ltlhe veiiicle lpygnnugrwgeed :greg chassis and ex end neary or zon a y an ln substantially parallel relationship. The working tiftitg n ctuatci'r leeifor lmtroltliing tlhe lvel parts of our loader attachment are all directly gh ef o'frh ca" er u ng i e nthre e em' lo or indirectly connected with said stress absorbing u reo f e Iisperientd lor s de o t gm h ever fem g he el; fat testis; oom struc ure, rus t mec an sm an ydraulic jacks are all provided by the said mountlllgs 12; gn th? out? portgnigf trboo] m28 ing frame and of predetermined relationship remssarringyogais lgxanlzi teiescogigg Wlh; gardless of the wheel base or other proportions the outer portions of the tubular upper side of of the tractor or other self-propelled vehicle to the link frame The 10a d carrier which may asi which our mechanism is applied' 55 sume a number of various attachment imple- Our apparatus includes a boom structure comments and forms is pivotal] inter Osed and prising an elongated, rigid pair of boom arms I2, connected betw er'i the outer Vend olf) th two the rear ends of which are pivoted and axially boom arms I2 srvmg when assemled toeaddi lgned upon heavy trunnions or pivot members tlonally interconnect the arms of the boom and which are aillxed and extend laterally from the t .nf th t n f th b t rear portion of the mounting tubes I0. Boom 0 re] ce e o er por on o e 00m s mc' arms I2 are of such length as to extend for some ture In the embodiment illustrated the load distance beyond the front end of the vehicle Carrier attached' comprisesatme'equipped scoop bucket well adapted for gathering and loading work always ln parallel, spaced relationship and material Such as manure boulders trash bum are interconnected and reinforced at their outer di s t Th s 0o buk t I8 has air of portions by equalizing linkage and the load care e c' e c p e a' p parallel end walls I8a rigidly secured to the rier itself, as will later be more fully developed bucket shaped bottom 'ab and is also provided The boom arms '2 adjacent their outer ends have with forwardly projecting rigid tines I8c adapted heavy upstandmg thrust'applymg lugs '2a rig" to gather and guide material to the bucket duridly connected therewith to which the elevating 7o ing thrust action upon the beams in lowered posi means in the form nism is connected.

The cantilever elevating mechanism includes a pair of transversely aligned, heavy bell crank levers I4 constructed as shown, from large triof a cantilever thrust mecha- 76 shown, are related to the center of gravity of the Medias empty bucket in such manner that the bucket v without a load would swing or dump forwardly without the addition of a restraining, counterbalancingforce. By reference to Fig. 8, it will be noted that in the load carrier construction. a. rigid torque tube IIT is welded throughout the length of the bucket to the scoop or back thereof as well as to the top of the bottom or tine cover, thus preventing twisting or sagging of the, load carrier through tilting and maintaining of uniform pitch due to its link connection Il with oneside of the boom structure only.

A releasable link connection is provided between one end oi' the bucket and the actuator lever extension i'le of one of the side links I1. This link connection includes a latch mechanism for releasing the bucket for dumping but has as essential features, a pivotal connection ila at its forward end with the adjacent end of the bucket and at a point widely eccentric of the bucket trunnions or pivots ip. The link connection indicated as an entirety by the numeral I9 is pivotally connected at its rear end with actuator lever extension ile of the linkage, by a pivot isb. Thus, lby means of the link structure i9, the bucket is slightly tilted during the elevation of the boom to elevate and maintain substantially the same pitch for properly retaining the load from the time the bucket has been raised off the ground throughout the elevation cycle.

The latch-equipped link connection i9 in the form shown, comprises a pair of elongated spaced bars I 9e disposed in parallel side by side relation and interconnected at their outer ends to the eccentric bucket pivot Isa. Said bars at their rear portions are welded or otherwise rigidly connected with a centrally disposed upper latch arm I9d extending longitudinally thereof and having a rearwardly projecting latch hook lSe provided with a shoulder formed in the upper longitudinal edge thereof. A bottom guide plate Isf is welded or otherwise afiixed to the bottom edges of the rear ends of slide bars lSc and with the lower edge of the latch arm ld and the opposed vertical faces of bars isc, forms a slide for receiving a bar which has affixed to the rear portion thereof, a bracket on which is plvoted the releasable latch member or dog 2i. The

` bar 20 extends throughout the greater part of the length of the spaced bars i90 and is con nected for relative sliding therewith and as shown, has welded or otherwise rigidly attached 4 to the outer end thereof, a guide channel member 20a which may comprise a pair of shallow, vertically disposed channel strips welded together and to the forward extremity of bar 20, dening channels on the outer iaces thereof wherein the spaced bars I9c are guided. The latch. pivoting bracket referred to, as shown, comprises a pair of vertically disposed rectangular plates 20h (Figs. 5 to 7) welded or otherwise atilxed to the side face of bar 20 near the rear end thereof andas shown, reinforced at the upper rear corners thereof by a transverse angle stopmember 20c, the upper spaced portions of rectangular plates 20h accommodating the latch member or catch hook 19e. The latch dog 2i at its working end is pivoted between rectangular plates 20h and is journaled thereon on a'pivot pin 20d having a tooth 2ia for engagement with the shoulder of catch arm isc and having an tremity o! which a cord or flexible operation element 23 is attached.

The pivot bolt IIb for attachment of the link connection il with the actuator lever Ile on one side of the cantilever linkage frame may be selectively received ior varying the pitch angle of the bucket or other load carrier by accommodation in any one of a series of transversely bored beari ing apertures e extending in longitudinally spaced relation through the lower portions of the bracket plates 1lb. The rear extremity oi' the bar Il has welded thereto, a cross head bracket 2|/ which is apertured at its ends for connection of a pair of heavy counter-balancing springs Il (see Fig. 6). said springs through bolt and nut connection being adjustable to connect at their rear ends with said bracket and having their forward ends connected with a cross pin which may constitute the pivotal connection bolt lla on the bucket. Stop or abutment blocksl IIb are secured to the inner faces of boom arms i2 projecting inwardly to prevent overswinging of the toggle linkage at a point ahead of dead center relationship of the pivots Il] and llc. These blocks will operate against the rearward edges of the link sides iid and both in elevation of the boom and in the subsequent dumping action of, a heavy load, will prevent unbuckiing of the toggle structure beyond the desired extended position.

Operation To gather or collect material upon the bucket or load carrier. the boom and other parts of the apparatus are lowered by releasing pressure of the hydraulic iiuid in cylinders il and the apparatus is disposed, as shown in Fig. 2. The tractor is then moved forwardly, the boom arms I2 placing a straight line thrust upon the load earrler with moet of the strain being distributed and imposed upon the heavy rear axle housing A. .Such thrust stress as is imposed upon the bell crank levers il, is distributed through the stress-absorbing frame comprising the tubular member Il.

.When the load carrier il is filled, the operator, through the control valve, actuates the hydraulic jacks, causing the jack pistons il to be projected forwardly and thereby operating the bell crank levers Il which, through their toggle connection with the' boom structure elevates the load carrier. Usually, it is desirable to elevate the load to the dotted line position shown in Fig. 2 for transportation to the place of dumping. In the carrying position of our apparatus with the boom struce ture disposed substantially horizontally, no parts are disposed above the hood and motor of the tracior and the vision of the driver is unencumbere When the vehicle has' transported the load to a truck, pile or other place of dumping, the boom structure is further elevated to the desired, raised position such as is shown in full lines in Figs. 1 and 3, the load being disposed stili forward of the lfront wheels of the vehicle.

Thereafter. the latch cord 23 maybe pulled to release the bucket for dumping, the weight of the load readily causing the bucket i3 to dump,

overcoming the slight counterbalancing eilect of the counterbalance springs il. After dumping,

the counterbalance springs return the bucket to upwardly and rearwardly extending rigid lever l arm 2lb which is normally urged forwardly by normal loading position and the latch mechanism is locked to cause the load carrier to be linkconnected with the upper extended end or actu- 'ator arm Ile of the cantilever linkage frame.

. eration without In the upward swinging of the boom structure (see Figs. 2 and 3), the pitch or angulation of the load-supporting portions of the load carrier Il. are automatically maintainedV to best advantage through the link connection I! with the upper actuator arm lle of the cantilever linkage frame i1. Thus, it will be noted (See Fig. 2) that in the initial lifting of the load from the ground, the bucket is tilted counterclockwise slightly and in the subsequent elevated positions (see Fig. 3), remains substantially at the same pitch or angulation. If a greater angulation or pitch is desired during the carrying position of the bucket I8 (see dotted lines position in Fig. 2) and throughout the subsequent elevation of the boom, the angulation may be varied but nevertheless maintained substantially constant by adjustment of the pivot pin |917 in the appropriate bearing aperture 20e of bracket 20.

Our improvedcantilever elevating mechanism materially improves the equalization or uniformity of power requirements throughout the entire elevating cycle of the apparatus. By the interposition of the cantilever linkage frame I1, properly proportioned and related with reference to the pivots of the elongated bell crank levers and the pivotal [connection with the boom structure, the range of thrust pressure required throughout the entire lifting arc is comparatively restricted as contrasted with the commercial embodiments of the structure disclosed in said earlier applica- 'tion of the applicant, Leo D. Pfau. Thus, in the lowered position of the boom, it will be noted that the cantilever frame Il is inclined rearwardly with respect to the boom and outer end of the bell crank triangles I4, applying leverage more efliciently in the initial load-breaking position than would be the case if a slidable or pin connection were made between the end of the bell cranks and the boom. In the subsequent elevating positions, particularly in the arc of elevation somewhat above the dotted line position in Fig. 3 to the extreme upper position, the toggle principle of application of thrust to the boom with its cantilever function, minimizes the power requirements as contrasted with bell crank lifting mechanism, the outer end of which is connected slidably with the boom structure. The longer arms of the bell cranks I4 and the height of cantilever linkage frame I1 and the relation of the pivotal points have been determined to obtain substantially a maximum lift with leverage application of power to minimize the power `requirements, particularly in the upper arc of elevation and in the initial lifting action, while enabling a straight line thrust from the hydraulic jacks tobe utilized against the short arms of the bell crank levers. It will further be noted that the same cantilever linkage is employed to maintain proper pitch or angulation of the load carrier throughout the entire elevating cycle.

It will further be seen that with our improved 1 structure regardless of the make, wheelbase, proportions or type of traction vehicle, the relation of the boom pivots I 3, bell crank pivots Itlc and attachment pivots Id of the jack structure, remain constant thus assuring highly eilcient oprequiring numerous adjustments for different types of tractors. It will further be seen that the stress-absorbing frame comprising the tubular members I0 and their rigid connection with the heavyaxle housing A and brackets at the forward portion of the chassis frame, result in a highly eillcient distribution of stresses during the elevation of the boom, the maintestructure upwardly.

nance of the boom in substantially horizontal, carrying position, and in maximum elevated position. With suchy structure, loads. in excess of two thousand pounds may be safely handled without danger of deforming or bendingportions of the vehicle chassis or any mountings thereon.

From the foregoing description, it will be seen that we have provided a highly efficient but nevertheless, quite simple front end loader construction adapted for substantially universal application to farm tractors and other traction vehicles now extensively utilized and adapted to withstand hard, continued usage with minimum wear on working parts.

It will of course, be understood that various changes may be made in the form, details, and arrangement of parts without departing from the scope of our invention.

What we claim is:

l. Material gathering and loading apparatus for a vehicle such as a tractor having in combination, a pair of interconnected boom arms swingably connected at their inner ends with the rear portion of a vehicle on a horizontal axis extending transversely of said vehicle and at a point below the top of the vehicle chassis, the forward ends of said arms extending beyond the front end of said vehicle, cantilever, boom-elevating mechanism adapted to also stabilize said boom, comprising precisely as essential elements a pair of lever arms lying substantially in vertical planes with the outer portions of said boom arms, the inner ends of said lever arms being pivoted on a common axis which extends transversely of the forward and lower portion of said .vehicle said lever arms extending forwardly cf said vehicle when said boom arms are lowered and a rectangular, rigid cantilever frame pivotally connected at its lower end to the outer ends of said for attaching a load carrier.

2. The structure set forth in claim 1 draulic jack connected with said vehicle and having a longitudinally projeetible element connected with said lever arms for swinging the same upwardly.

3. The structure set forth in claim 1 wherein said lever arms are in the form of bell cranks and power actuated, longitudinally projectible means connected with said vehicle and connected to corresponding arms of said bell cranks for actuating the same.

4. Material-carrying and loading apparatus for a vehicle such as a tractor having in combination a boom structure comprising a pair of spaced and a hyof a rigid, pivotally connected end to the two lower arms of said toggle structure and having spaced pivotal connections at its upper end with the outer portions of said boom arms and power means for swinging the lower arms of said toggle 5. Material-carrying and loading apparatus for a vehicle such as a tractor having in comvehicle chassis, said arms at their outer ends extending atleast to the opposite end of said vehicle,

a load carrier pivotally connected to the forward l ends of said boom arms, boom-elevating and stabilizing mechanism comprising a toggle structure having a pair of longer lower arms pivoted on a common transverse axis adjacent the opposite end of the vehicle and comprising an upper cantilever message in the form of a generally rectangular rigid member pivotally connected at its lower end to the two lower arms of said toggle structure and having pivotal connections at its upper end with the outer portions of said boom arms, said cantilever linkage having an actuator am extending above its pivotal connection with said boom and a link connecting said actuator arm with a point above `and eccentric of the axis `of said load carrier for maintaining. the pitch o said load carrier substantially constant throughout the elevation of said boom and power i means for swinging the lower arms of said toggle structure upwardly.

6. Material gathering and loading apparatus for a vehicle such as a tractor, having in combination a boom structure adapted to be swingably connected at its inner end with an end portion of the vehicle and extending at its outer end beyond the opposite end of said vehicle, a load carrier pivotally attached to the outer end of said boom structure for swinging on a horizontal axis disposed transversely of the vehicle, a toggle boom elevating mechanism interposed between the outer end of said boom structure and the adjacent end of said vehicle, said toggle having a lower arm pivoted to the vehicle and having an upper arm pivoted to said boom structure, power means for swinging the lower arm of said toggle upwardly, the upper arm of said toggle having an actuator extension disposed beyond 4 the pivot of said arm with the boom structure and a link connecting said actuator extension with e said load carrier at a point disposed above and eccentric of the axis of said load carrier for maintaining the pitch of said load carrier substantially constant throughout the elevation of said boom.

7. Material-carrying and loading apparatus for a vehicle such as a tractor, having in combination a boom structure adapted to be swingably connected at its inner end with the lower rear portion of a vehicle and extending at its forward end to at least theforward end of said vehicle, underlift boom-elevating mechanism comprising a forwardly jack-kniilng toggle structure having its lower linkage pivoted to the lower QI'WliId POIUOII 0f the Vehicle on a transverse axis and having its upper linkage 11n lhe )crm o] a 5 rigid, substantially rectangular frame pivoted at spaced axially aligned points to the outer portion of said boom structure and a hydraulic jack connected with said lower linkage to swing the same upwardly and to thereby elevate said boom by l0 cantilever action and means for attaching a loadcarrier to the outer end of said boom.

8. Material-carrying and loading apparatus for a vehicle such as a tractor, having in combination a boom structure adapted to be swing- 15 ably connected at-its inner end with an end portion of the vehicle on a. transverse axis at a. low level on the chassis and extending at its outer end to at least the opposite end of said vehicle, means adjacent the outer end of said boom structure for attaching a load carrier thereto and boom-elevating and stabilizing mechanism comprising a bell crank lever structure having its ulcrum pivoted on an axis extending transversely of the last mentioned end portion of the vehicle, said bell crank structure having a thrustreceiving arm and an upwardly swingable lift arm, power means for imparting thrust against said thrust-receiving arm and a link structure connecting the outer end of saidliit arm with the outer portion of said boom structure, said link structure comprising a rigid, generally rectangular frame disposed transversely of said vehicle and having spaced connections at its lower end with said bell crank structure and having spaced connections at its upper end with said boom structure to stabilize the latter during elevation of a load. f

. LEO D. PFAU. ROBERT D. TUFFORD. 4o JOSEPH E. MAYER.

REFERENCES CITED The following references are of record in the 5 le of this patent:

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